Year years 1960 59.675 1961 59.996 1962 60.271 1963 60.527 1964 60.781 1965 61.045 1966 61.334 1967 61.63 1968 61.909 1969 62.173 1970 62.429 1971 62.681 1972 62.936 1973 63.206 1974 63.501 1975 63.889 1976 64.378 1977 64.936 1978 65.549 1979 66.235 1980 67.14 1981 68.012 1982 68.884 1983 69.804 1984 70.772 1985 71.644 1986 72.471 1987 72.897 1988 73.468 1989 73.787 1990 73.983 1991 74.149 1992 74.419 1993 74.804 1994 75.311 1995 76.008 1996 76.833 1997 77.7 1998 78.386 1999 79.18 2000 79.536 2001 79.685 2002 79.711 2003 79.703 2004 79.696 2005 79.736 2006 79.842 2007 80.02 2008 80.301 2009 80.665 2010 81.039 2011 81.429 2012 81.759 2013 82.017 2014 82.214 2015 82.354 2016 82.488 2017 82.618 2018 82.783 2019 82.996 2020 82.217 2021 79.486 2022 83.55